1. Field of the Invention
The present invention relates generally to a structure of a disc drive apparatus, for example, suitable for a floppy disc drive apparatus.
2. Description of Prior Art
Recently, a disc drive apparatus such as a floppy disc drive apparatus has remarkably and widely been used in a commercially available personal computer, office computer, word processor, and so on.
FIG. 10 shows a structure of a kind of the disc drive apparatus previously proposed.
As shown in FIG. 10, a chassis denoted by 1 is provided in which a spindle of a motor 2 serving as a center of rotation of a disc is built in. For example, the chassis 1 is housed in a frame of equipment (not shown) of, e.g., a personal computer. The whole chassis 1 is open toward its forward direction and is formed of a box having a bottom end and having a housing space 1a to which a disc cartridge 3 is exposed. A retaining wall 4 and a supporting axle 5 are vertically extended from a rear right side portion of the bottom end of the chassis 1 as viewed from FIG. 10. The retaining wall 4 is provided with a penetrated hole 4a which opens in the forward and rearward directions and the supporting axle 5 is juxtaposed to the retaining wall 4 with a predetermined interval of distance therebetween. Two spring engagement/stop pieces 6 are projected from forward ends of the chassis 1 and juxtaposed to each other with predetermined interval of distance in respective rightward and leftward directions.
A plurality of guide grooves 7 (in FIG. 10, only two guide grooves in the left side are shown) extending upward and downward directions are integrally mounted on both side walls of the chassis 1.
Two pairs of projectors 8 and 9 are juxtaposed respectively to each other with predetermined intervals of distances in the forward and rearward directions of the chassis 1.
The two pairs of projectors 8 and 9 are mounted on the bottom end of the chassis 1 and are so constructed as to enable a sliding plate to be described later to be guided in the forward and rearward directions. One of each pair of projectors 8 and 9 is juxtaposed to the other of each pair of projectors 8 and 9 with the predetermined interval of distance in the rightward and leftward directions.
A cartridge positioning portion 9a having a conical shape is installed in each of rear-sided pair of projectors 9, whose outer diameter is such as to become smaller as the portion 9a advances to its tip.
A sliding plate 10 having a letter C-shaped cross section is provided with an "eject" button 11 which is pushed to ON to eject the disc cartridge 3 from the plate 10, the eject button 11 being placed at a right side portion of a forward end edge of the plate 10.
The sliding plate 10 includes: a bottom surface plate 12 having a cut-out 12a of a totally U shape viewed from the top of the chassis 1 to which the spindle of the motor 2 is exposed and having a first elongated hole 12b to which the spring engagement/stop piece 6 is exposed; and two side plates 13 extended at both side portions of the plate 10 and opposing to each other with a predetermined interval of distance. The two side plates 13 are so constructed in the chassis 1 as to be enabled to be advanced and retracted in the chassis 1.
A cut-out 14 and a spring engagement/stop hole 16 are disposed on the bottom surface plates 12 of the sliding plate 10. The cut-out 14, to which the respective pairs of projectors 8 and 9 are exposed, is extended in the forward and rearward directions. The spring engagement/stop hole 16 corresponds to a second elongated hole 15 and the spring engagement/stop piece 6. In addition, a lock pawl 17 is installed which is projected downward at the rear side edge of the bottom plate 12 of the sliding plate 10.
On the other hand, front, rear, right, and left cam grooves 18 are formed on the bottom surface plate 12 of the sliding plate 10, each having a gradient obliquely raised in the forward directions and a rack 19 is provided at the rear position of the left cam groove 18, the rack 19 being extended in the forward and rearward directions.
Two coil springs 20 bias the sliding plate 10 in the forward direction and have both ends which are engaged with the respective spring engagement/stop piece 6 and respective spring engagement/stop hole 16.
A trigger arm 21 has an engagement surface 21a and a guide surface 21b which are opposed to the lock pawl 17. The trigger arm 21 is pivotally disposed on the supporting axle 5 and an arm operator 22 is integrally mounted on an upper end surface of the trigger arm 21, the arm operator 22 being provided with a tongue 22a projected toward a side of the trigger arm 21 so as to be engaged with a spring to be described later.
A torsion spring 23 is biased to pivot the trigger arm 21 in a direction at which the sliding plate 10 is engaged, its winding portion of the torsion spring 23 is mounted at a peripheral side of the supporting axle 5, and its both ends are engaged and stopped at the tongue 22a and retaining wall 4.
A stepping motor 24 for a head carriage feed is fixed on a rear end portion of the chassis 1. An output axle 25 of the stepping motor 24 is extended in the forward and rearward directions and is formed with a reed screw axle extended in the forward and rearward directions and having a V-shaped groove 25a in a spiral form, its tip being supported via a bearing (not shown) within the penetrated hole 4a of the retaining hole 4.
A guide axle 26 extended in the forward and rearward directions is retained on a rear center portion of the chassis 1 and is so constructed as to guide a head carriage to be described later in the forward and rearward directions.
A head carriage 27 is provided with a needle pin 28 and a plate spring 29 by means of which the needle pin 28 is brought in close contact within the V-shaped groove 25a of the output axle 25 under pressure, and is held so as to be enabled to be advanced and retracted in the upward direction of the chassis 1, and an axial hole 27a (shown in FIG. 11) is provided at the right-and-lower side of the head carriage 27 through which the guide axle 26 is penetrated via a bushing B (shown in FIG. 11). A first head 30 to read a recorded information on the disc is held on an upper end of the head carriage 27 and a head arm 32 having a second head 31 corresponding to the first head 30 is swingably attached onto a rear-and-upper side of the head carriage 27 via an elastic material 33.
The head arm 32 is pivotally biased by means of the torsion spring 34 in a direction at which the second head 31 approaches the first head 30 and is integrally mounted with a stopper 32a used to limit the pivotal movement of the head arm 32 and which is projected toward a side of the head arm 32 from a side end edge of the head arm 32 (as shown in FIG. 12).
A cartridge holder 36 is installed within the sliding plate 10 so as to be enabled to be moved in the upward and downward directions. The cartridge holder 36 removably holds the disc cartridge 3 so as to be enabled to be inserted into or drawn from the cartridge holder 36.
A roller 37 is rotatably held on both side ends of the cartridge holder 36. The roller 37 having its recess is exposed to the respective cam grooves 18 and guide grooves 7. A vertical tongue 38 is installed at a side edge of the upper end of the cartridge holder 36. The vertical edge 38 is provided with an engagement/stop hole 38a which opens in both side directions of the vertical edge 38. Then, the cartridge holder 36 is so constructed as to engage or release the lock pawl 17 and engagement surface 21a to or from each other under a pressing force (pressure) of the disc cartridge 3 against the arm operator 22, thus approaching the bottom end plate 12 by means of the rearward movement of the sliding plate 10 under the pressing force (pressure) from the eject button 11 and being spaced apart from the bottom surface plate 12.
An arm 39 which opens and closes a shutter 3a of the disc cartridge 3 is pivotally mounted on a side edge of the rear-and-upper side of the cartridge holder 36. The arm 39 is integrally formed with an engagement/stop piece 40 which is projected upward.
A coil spring 41 pulls the arm 39 so as to provide a return characteristic for the arm 39 and has both ends which are engaged to the engagement/stop piece 40 and engagement/stop hole 38a.
Switches 42 and 43 are mounted on the chassis 1 via a p.c. board 44 for detecting kinds of discs D (for example, 2DD, 2HD, or 3ED) and for detecting permission or disablement of writing onto the disc (not shown), respectively.
A speed-reduction gear mechanism 45 is disposed on a side edge of the rear end portion of the chassis 1. The speed-reduction gear mechanism 45 is provided with a gear 46 which meshes with the rack 19.
Furthermore, positioning recesses 47 and 48 are provided in a casing 3b of the disc cartridge 3, through which the respective projectors 9 get into or get off the casing 3b.
Anyway, a head alignment of the head assembly in the kind of the disc drive apparatus shown in FIG. 10 is carried out as follows:
That is to say, a jig (not shown) used to adhere a head chip and having two supporters (not shown) is prepared, one of the two supporters of the jig being inserted into the bushing B of the head carriage 27 shown in FIG. 11 and the needle pin 28 being mounted on the other supporter so that the head alignment is carried out with a degree of parallel (juxtaposition) maintained.
In this case, a vertical distance shown in FIG. 11 between the one supporter (a horizontal center line of the bushing B) and the other supporter (a supported point of the needle pin 28) is set to 6.30 mm.
However, since in the head assembly of the disc apparatus shown in FIG. 10 has the head carriage 27 and needle pin 28 which are respectively formed of a synthetic resin and stainless steel, it is necessary to mount the needle pin 28 on the head carriage 27 during its assembly of the head. Consequently, numbers of mounting steps in the head assembly are increased and the assembly cost of the disc drive apparatus becomes high as described above.
Furthermore, in the kind of the disc drive apparatus shown in FIG. 10, the needle pin 28 is pressurized and brought in close contact with an outer peripheral surface of the output axle 25 by means of the plate spring 29 and an inner peripheral surface of the bushing B is brought in close contact with the outer peripheral surface of the guide axle 26 by means of the torsion spring S, as shown in FIG. 11 in order to secure a transmission of a driving force of the stepping motor 24 and maintain a magnitude of balance of a head assembly of the disc drive apparatus. Therefore, two springs (namely, the plate spring 29 and torsion spring S) are needed.
Consequently, an assembly labor-hour cost as well as number of assembly parts are required so that a assembly cost of the disc drive apparatus becomes high as a total.
Still furthermore, since, in the head assembly of such a kind of the disc drive apparatus as described above, the head arm 32 is swingably held on the head carriage 27 and the head arm 32 is pivotally biased in the direction such that the second head 31 approaches the first head 30, two parts of the press plate P to integrate the head carriage 27 and head arm 32 and of the spring mounting pieces S to mount the torsion spring 34 onto the head carriage 27 are required. Consequently, the labor-hour of assembly is increased as well as the number of parts to be assembled so that the assembly cost becomes high as the total.